Many actors claim that an understanding of psychology is essential for the creation of believable characters. Janice Rule, who has died aged 72, became so fascinated by what made the characters she played tick that she took this interest to its logical conclusion by becoming a professional psychoanalyst.

This followed a distinguished acting career in films, on stage and on television, which began in 1951 at the age of 20, when the former Ohio-born showgirl and nightclub singer signed a contract with Warner Bros. For the first years, the parts of a pretty ingenue required little analysis, although she was able to observe the on and off-screen histrionics of Joan Crawford in Goodbye My Fancy (1951), Rule's debut film. For some reason, the 47-year-old Crawford resented the younger woman's presence on set, and Rule was dismissed by the studio after one further film.

In 1953, she got her first break on Broadway by appearing in William Inge's Picnic as Madge Owens, the naive beauty queen (played in the film by Kim Novak). Also making his Broadway debut in the play, directed by Joshua Logan, was Paul Newman, who played her respectable boyfriend.

Her co-star in Picnic, Ralph Meeker, got her the part of his wife in the murky thriller A Woman's Devotion (1956), directed by Casablanca actor Paul Henreid. Now back in films as a freelance, Rule provided Fred MacMurray's romantic interest in Gun For A Coward (1957), and in Bell, Book And Candle (1958), she was publisher James Stewart's strait-laced fiancee, who loses him when he is literally bewitched by Kim Novak.

In the same year, on Broadway in Michael V Gazzo's The Night Circus, she was praised for her performance as a beautiful, restless girl, who destroys others on the way to destroying herself. Although the depressing play ran only seven nights, it was significant in two ways. It indicated that Rule could portray destructive women, and playing opposite her was Ben Gazzara, to whom she would be married from 1961 to 1979. Rule had previously been married to writer-director Robert Thom and playwright N Richard Nash.

Some of her better roles on screen, after The Night Circus, were as bitter, neurotic socialites such as the sluttish wife of Robert Duvall in The Chase (1966), who drunkenly swallows a string of precious pearls, and as Burt Lancaster's violently vitriolic ex-wife in The Swimmer (1968), who claims never to have loved him.

She was also sexy and sassy in several Westerns such as Invitation To A Gunfighter (1964) with Yul Brynner, and in Alvarez Kelly (1966), where she is described by antagonistic cattleman William Holden to her fiance, Confederate officer Richard Widmark, as "just a female, not a crinoline saint".

The 5ft 6in Rule - who was once quoted as saying that "it outrages me that what are considered graces in men like height and intelligence are considered gaucheries in women" - began acting less and less in the 1970s.

However, she did come to Britain to appear in Gumshoe (1971), Stephen Frears' debut film, a homage to film noir, and was an ageing whore in Kid Blue (1973), a hippie Western starring Dennis Hopper.

But one of her most spellbinding roles was in Robert Altman's Jungian drama Three Women (1977), as a mute, heavily pregnant artist, who puts her fears of male aggression into mythic murals. At the same time, she was studying psychology and received a PhD in 1983 from the Southern California Psychoanalytic Institute in Los Angeles.

She is survived by her daughters, Kate Thom Fitzgerald and Elizabeth Gazzara.